Alternating-current relay



May 7, 1929. I T y 1,711,550

ALTERNATING CURRE NT RELAY Patented May 7, 1929.

UNITED STAT S PATENT OFFICE.

WILLIAM w.v STURDY, isnooKLYn, new YonK, .nssreivon 'ro AMERICAN 'rnniirnoivn 'AND TELEGRAPH COMPANY, A CORPORATION OF NEW 'YORK.'

ALT E ENATING-CURRENT Y RELAY.

Application filed August 8,1925; Serial No. 48,638.

This invention relates-to relays, and more particularly to alternating current relays for use in carrier telegraph circuits.

One object of the invention is to provide an alternating current relay which can be used incarrier telegraph circuitswithout ie ceiving filters or with fewer receiving filter sections than are required with the r lays heretofore employed. Other objects and advantages of the improved relay will be made clear in the foliowing description.

The relay is a polar relay having a ribbon armature, of magnetic material, which vibrates between two electromagnets and is mechanically tuned to thedesired natural frequency of vibration.

The following detailed description of the;

relay and the associated circuits is to be read with reference to the accompanying draw ing. Figure 1 of the drawing is, a top view of the device, partly in section, and Fig. 2 represents a side View, likewisepartly in sec-- tion. Fig. 8 is a diagram showing the magnetic flux in the cores of the electromagnets and the armature during the first half-cycle of thealternating current. Fig. 1 shows the same during the second half-cycle. Fig. 5 is a circuit diagram showing the carrier telegraph receiving circuits -including two of applicants relays and a reduced number of receiving filter sections, and Fig. 6 shows similar circuits .without receiving filters.

, Like characters of reference in the several figures oi? the drawing designate correspoinling parts.

Tith reference to the details oi the draw ing, and :lirst with particular reference to Figs. 1 and 2, the U-shaped cores 1 and 2 are energized by the direct current coils 3 and 1, respectively, these coils being wound so as to give to the cores the polarity indicated in Fig. 1. The ribbon armature 5 is ofa magnetic material of low hysteresis, such as perm- ;dlo'y, and carries the contacts 6 and 7, one on either side. The tension of the armature may be adjusted by suitable mechanical means',such as the device shown in the draw ing and consistingof the member 8, which is attached to one end of the ribbon, and the adjusting screw 9, which controls the position of said member. Thelock-nut 10 is provided to keep the tension substantially constant after adjustment has been made. The coils 11 and 12, surrounding the mid-section or" the armature, carry the altcrnatlng current from the line.

j The strip springs 13 and 14, of honanagnctic material, are carried on the supports 15 and 16, also of nonmagnetic material, and are connected in serieswith the local direct current neutral relay circuit (see Figs. a and 5). When no'alternating currentis flowing over the line, these springs 13 and 14- make contact with the armature contacts 6 and 7, respec- I tively, through the spring contacts 17 and 18 (see Fig. 1). a

With particular reference to Figs. 3 and l, the direct current coils are wound about the coresl and 2 so that the magnetic flux set up by the one coil, representedby the solid unt'eathered arrows, and the flu}: setup by the other coil, represented by the broken unfeathered arrows, oii'set each other in the armature 5. As indicated above, the result is that, with no alternating current in the line, contact is made and remains made between the armature contacts 6 and 'Z' and the spring contacts 17 and 18, closing the circuit oi the neutral relay. The body of the arma ture is notin. the-electrical circuit. When alternating current flows in the line and in the alternating current coils,the first half of the cycle adds algebraically to the magnetic fluxes caused by the direct current the flux represented by the solid :teathered arrows, as shown in Fig. 23. The strengthening of the flux in the air-gaps on one side of the armature and the weakening of the link in the airgaps on the other side cause the armature 5 to cycle the fluxes set up areas shown in F 4,

the flux represented by the broken feathered relay circuit. During the second half ofthe V arrows being that due to the alternating current. The result is that-the armature is moved in the other direction. 7 I

The springslland 15, as indicated above, are oi non-magnetic material, and should'be,

of such dimensions and elasticity'that their natural period 01": vibration lies between the ingalternating current, the armature breaks contact with one spring before making contact with the other, and consequently the local circuit of the neutral relay is kept open during the entire period of the incoming ma ll:- l signal. At the termination of the marl:-

V signal, the armature ceases to vibrate, and the spring contacts return to their original positions, closing the neutral relay circuit.

By the means scribed above-01 other suitable 1ncansfor adjusting the tension of the ribbon, the armature 5 can be tuned to the desired frequency, and the loch-nut serves to keep the tension substantially constant durin g operation of the relay. The relay should, of corn so, be made quite selective, as the nuniher of receiving filter sections heretofore used in carrier telegraph circuits can thereby be materially reduced (see F If the relay is made sufliciently selective, it is readily understood that all receiving iilterscan be eliminated Fig. 6).

It is to be understood that, while applicant has specifically described his invention in one embodiment, which is ClQQll'ltl'Cl6Sll'- able, various changes from that embodiment may be made without departing from the spirit of the invention, which is defined in the appended claims.

l l hat is claimed is:

1. An alternating current relay comprising an alternating current coil, an armature,

adjusting the natural frequency of vibration of said armature.

2. An alternating current relaycompris- 'ing an armature, electromagnetic means for causing said armature to vibrate in response to alternating current flow, means :l'or ad'- 'ustin the natural fre none of vibration ot the armature, and two springs so constructed and positioned that normally both springs make contact wlth the armature but "duringthe flow of alternating current only one spring at a time makes contactwith the armature.

3. An alternating current relay con'iprising two electromagnets, an alternating current coil, an armature designed to vibrate between said electromagnets in response to current flow in said coil, two springs normally in a line and a local direct current neutral relay circuit, means for breaking said circuit in response to alternating current coming in over said line, said means consisting of an an alternating current relay comprising an armature, electromagnetic means :lor causing said armature to vibrate 111 response to alternating current coming in over said line,

means associated with said armature lor breaking the circuit of the direct current relay during the vibration or the armature, and means for adjusting the natural irequency of vibration of the armi'zture.

6. In a carrier telegraph system includin a line and a local direct current neutral relay, an alternating current relay comprising two electromagnets, an alternating current coil in series with the line, an armature de, gned to vibrate between said electromagnets in response to current flow in the line, two springs in se *ies with the neutral relay and'normally in contact with said armature, the vibration of said armature causing the same to break contact with said springs alternately, and means for adjusting the natural frequency of vibration of said armature. i 7. In a carrier telegraph system including a line and a local direct current neutral relay, an alternating current relay comprising an alternating current coil in series with the line, a source of direct current, two electromagnets having their coils in series with said source, an armature designed to vibrate be tween said electromagnets in response to alternating current flow in the line, means associated with said armature for brealri the neutral relay circuit durii the vibration oi" the aru'iature, and means adjusting the natural frequency oi? vibration of the ariuature. V

8. ln a carrier telegraph systcn'i including a line and a local direct current neutral relay circuit, an alternating current relay for breaking the neutral relay circuit in response to alternating currentiiow in the line, said alternating current relay comprising an armature, electromagnetic means for causing said armature to vibrate in response to current flow in the line, two springs in series with said neutral relay and normally in contact with said armature, the vibration of said armature causing the same to break contact with said springs alternately, and means for adjusting the natural of said armature.

In testimony whereof, I have signed my name to this specification this 4th day of August, 1925. 7

WILLIAM w. STURDY.

frequency of vibration 

